Method for producing monocarbonyl compounds or biscarbonyl compounds or hydroxyl compounds

ABSTRACT

The invention relates to a method for producing monocarbonyl compounds or biscarbonyl compounds or hydroxyl compounds by ozonizing, unsaturated organic carbon compounds that, per molecule, have one or more olefinic or aromatic double bonds, which can be cleaved by ozone, and by subsequently processing the ozonization products. According to the inventive method, unsaturated organic carbon compounds that, per molecule, have one or more olefinic or aromatic double bonds, which can be cleaved by ozone, are: (a) in 1 to 2 steps, continuously reacted with ozone in stoichiometric quantities or in excess while using counter educt currents and being in an organic solvent or in an aqueous solution inside a device, which consists of one to two absorption apparatuses, of devices for carrying away reaction heat, and of devices for separating the gas and liquid phases, and; (b) the peroxides resulting therefrom are, according to reaction parameters from step (a), converted into the corresponding monocarbonyl compounds or biscarbonyl compounds or hydroxyl compounds either by continuous or discontinuous hydrogenation, oxidation or heating.

[0001] The invention relates to a process for the preparation ofmonocarbonyl or biscarbonyl or hydroxyl compounds from unsaturatedorganic carbon compounds having one or more olefinic or aromatic doublebonds in the molecule.

[0002] The ozonolysis of olefins gives, in an environmentally friendlymanner, carbonyl compounds, such as aldehydes or ketones, or, dependingon the work-up conditions, their hemiacetals, acetals or ketals, andalso hydroxyl compounds which represent valuable starting materials inpreparative organic chemistry.

[0003] The preparation of carbonyl or hydroxyl compounds from organiccompounds which have, as structural element, one or more C═C doublebonds in the molecule by means of a two-stage ozonolysis and reductionprocess is known. In carrying out this method, the first stage in mostcases uses an excess of ozone in order to achieve as complete aspossible ozonization of the double bond. The reductive cleavage, whichtakes place in the second stage, presents problems again and again sincethe peroxide-containing ozonization products are unstable and, in theabsence of metallic hydrogenation catalysts, undergo rearrangements ordecomposition particularly readily before they can be reduced to thecorresponding carbonyl compounds. Furthermore, in the case of noblemetal catalysts and prolonged contact with peroxide-containingsolutions, losses in activity of the catalyst have been observed,meaning that the solutions do not usually become entirely peroxide-freeupon reductive cleavage by hydrogenation and, in addition to thedifficulties with isolation of the end-products, losses in yield and arisk of explosion also have to be accepted. To avoid these difficulties,U.S. Pat. No. 3,145,232 recommends a process for the preparation ofcarbonyl compounds in which the reductive cleavage is carried out afterthe ozonolysis at temperatures below −40° C. in the presence of atrialkyl phosphite. As well as the high expenditure on apparatus forproducing the extremely low reaction temperatures, such a reactionprocedure requires the use of absolutely anhydrous solvents since thetrialkyl phosphites are hydrolyzed extremely rapidly in hydroussolvents. Furthermore, separation of the free carbonyl compounds fromthe phosphate esters which form during the reduction presentsconsiderable difficulties.

[0004] Since it has been demonstrated that low reaction temperatureshave a disadvantageous effect on the activity of the reducing agentused, resulting in losses in yield, according to a process for thepreparation of aliphatic, aromatic and heteroaromatic aldehydes as isdescribed in U.S. Pat. No. 3,637,721, although the ozonolysis of the C═Cdouble bond is carried out at −50° C., while the reaction temperaturesduring the course of the reductive cleavage of the ozonization productswith aromatic or aliphatic disulfides is increased to 50° C. However, insaid process, separation of the sulfoxides which form as secondaryproducts during the reduction, for example dimethyl sulfoxide, from thealdehydes which form as process products has turned out to be extremelydifficult and cannot be carried out at all in many cases withoutderivatization of the aldehydes.

[0005] Finally, U.S. Pat. No. 3,705,922 or DE-A-2 514 001 describe thepreparation of carbonyl compounds by means of an ozonolysis andreduction process in which the unsaturated compounds serving as startingmaterial are reacted with an excess of ozone, and the ozonizationproducts formed in the process are reductively cleaved by catalytichydrogenation. However, in the process, excess ozone must again beremoved prior to the reductive cleavage to protect the hydrogenationcatalyst against losses in activity by flushing the reaction solutionwith an inert gas, for example with nitrogen, in a suitable processingoperation.

[0006] To carry out the hydrogenation, the catalyst, which is preferablya noble metal catalyst, is, then, added directly to the reaction mixtureformed during the ozonolysis, and hydrogen is introduced to saturation.

[0007] Since noble metal catalysts are deactivated upon prolongedcontact with organic peroxides, in the known processes the yield duringthe hydrogenation depends on the amount of hydrogenation catalyst usedin each case. As is clear from a comparison of the examples in U.S. Pat.No. 3,705,922, the yield decreases by about 10% despite acorrespondingly extended reaction time if, for the same size batch, only0.2 g of a Pd/Al₂O₃ catalyst are used in place of 0.5 g. However, saidpublications give no details on the possibilities of regeneration orreuse of the noble metal catalysts used when the hydrogenation iscomplete either.

[0008] Processes for the preparation of carbonyl compounds, theirhemiacetals, acetals or ketals by ozonolysis and reduction which aim toavoid the above disadvantages and which are carried out on an industrialscale are described in EP-B-0 146 784 or EP-B-0 147 593. According tothe disclosure of these two patent specifications, compounds which haveolefinic double bonds are reacted in a lower aliphatic alcohol attemperatures of from −80° C. to 20° C. with the equivalent amount ofozone, and then the peroxidic reaction solution is fed into a suspensionof a hydrogenation catalyst with the addition of hydrogen in a mannersuch that the peroxide concentration in the reaction mixture does notexceed 0.1 mol/l. Since this type of reaction procedure produces acidicsecondary products which would poison and rapidly deactivate thecatalyst, the pH of the reaction mixture has to be controlled by addinga base.

[0009] In the process variants known hitherto, both the ozonolysis stepand also the hydrogenation are carried out batchwise. The excess ofozone which is used in most cases also has a negative effect in the caseof these processes since, for example, it has to be blown out usinginert gas prior to the hydrogenation step.

[0010] DE 27 13 863 describes a continuous ozonolysis, in particular oflong-chain or higher molecular weight compounds, such as olefins, oleicacid or linoleic acid, in the presence of water. The water is used herein place of an external cooling cycle and thus serves for the in situdissipation of the heat of the reaction. This process is only forrapidly reacting substrates, such as oleic acid and only for aqueoussystems, not for purely organic systems which, however, are used for thegreater part in the ozonolysis.

[0011] Surprisingly it has now been found that the disadvantagesassociated with the known processes can be avoided according to thepresent invention by a simple and economic process in which, in acontinuous procedure, an unsaturated organic carbon compound having oneor more olefinic or aromatic double bonds is reacted, despite knowndisadvantages, with an excess of ozone, and then the peroxide-containingozonization products, likewise in a continuous procedure in dilutesolution at a low concentration of peroxides, are rapidly reductivelycleaved or converted into the desired end products by means of oxidationor simple heating.

[0012] In comparison with the known processes, the process according tothe present invention gives carbonyl or hydroxyl compounds in acomparable yield and purity by the continuous processing method in amore simple and more economic way, with the constant and easy-to-controlparameters, the reduced requirement for monitoring and the lowerperoxide content in the plant having proven particularly advantageous.In the process according to the invention, the catalysts are preservedand in no way chemically poisoned during a prolonged period ofoperation, meaning that, firstly, they remain stable for years and,secondly, do not exhibit noticeable loss in activity even withoutregeneration and work-up upon reuse. All of these advantagous propertiescould not have been expected in view of the prior art.

[0013] Accordingly, the present invention provides a process for thepreparation of monocarbonyl or biscarbonyl or hydroxyl compounds byozonization of unsaturated organic carbon compounds which have one ormore olefinic or aromatic double bonds which can be cleaved by ozone inthe molecule, and subsequent work-up of the ozonization products, whichcomprises reacting unsaturated organic carbon compounds which have oneor more olefinic or aromatic double bonds which can be cleaved by ozonein the molecule,

[0014] a) in an organic solvent or in aqueous solution in 1 to 2 stepscontinuously in equipment consisting of one to two absorptionapparatuses, devices for dissipating heat of the reaction and devicesfor separating the gas and liquid phase, with countercurrent reactantstreams, with ozone in stoichiometric amounts or in excess and

[0015] b) converting the peroxides which form into the correspondingmonocarbonyl or biscarbonyl or hydroxyl compounds either by continuousor discontinuous hydrogenation, oxidation or heating, depending on thereaction parameters from step a).

[0016] The process according to the invention can be used to prepare alarge number of very different monocarbonyl or biscarbonyl or hydroxylcompounds.

[0017] Examples thereof are monocarbonyl or biscarbonyl or hydroxylcompounds of the formula I

[0018] in which

[0019] Z is either OH or O and A, when Z is OH, is a single bond and,when Z is O, is a double bond

[0020] Q is hydrogen or the radicals

[0021] where R₁ is H or an ester moiety derived from chiral or nonchiralprimary, secondary or tertiary alcohols,

[0022] X is a straight-chain or branched mono- or divalant, aliphaticalkyl or alkylene radical having 1 to 50 carbon atoms, where this alkylor alkylene radical may be substituted by one or more groups which areinert under the reaction conditions; an optionally substituted,straight-chain or branched aliphatic alkyl or alkenyl radical having 2to 50 carbon atoms, where one or more of the —CH₂ groups of the alkyl oralkylene chain is replaced by an oxygen atom, a nitrogen atom, a sulfuratom or an —SO₂ group; a radical of the formula—(CH₂)_(m)—O—CO—(CH₂)_(p), where m may be an integer from 1 to 4 and pmay be an integer from 1 to 6; a phenyl or phenylene radical, where thisphenyl or phenylene radical may be substituted by one or more groupswhich are inert under the reaction conditions; a mono- or divalentalkylarylene or alkylene-arylene radical having 7 to 50 carbon atoms,where these radicals may be substituted by one or more groups which areinert under the reaction conditions; an optionally substitutedheterocycle with one or two heteroatoms in the ring or a single bondbetween two adjacent carbon atoms, and

[0023] R is hydrogen, a C₁ to C₂₀-alkyl radical, —OR₁ or the radical

[0024] or X and R together form a mono- or bicyclic radical having 4 to20 carbon atoms which may be mono- or polysubstituted by groups whichare inert under the reaction conditions, are prepared.

[0025] Ester moiety derived from chiral or nonchiral alcohols is to beunderstood as meaning esters of primary, secondary or tertiary alcohols.Esters of primary alcohols are preferably derived from methanol,ethanol, butanol, propanol or hexanol. Esters of secondary or tertiaryalcohols are preferably derived from acyclic, monocyclic, bicyclic,terpene alcohols, from acyclic, monocyclic, tricyclic, sesquiterpenealcohols, di- or triterpene alcohols which may be optionallysubstituted.

[0026] Examples of suitable substituents which are inert under thereaction conditions are:

[0027] C₁-C₂₀-alkyl or alkoxy or alkylalkoxy groups, such as, forexample, methyl, ethyl, isopropyl, butyl, hexyl, octyl decyl, dodecyl,methoxy, ethoxy, butoxy, hexoxy, methoxymethyl, methoxyethyl,ethoxymetyl, ethoxyethyl, etc.;

[0028] nitro, halogen, hydroxyl, CN, CONH₂, carboxyl, carboxylate,amino, SO₃H groups, etc.

[0029] Compounds which can be prepared are, for example, benzaldehyde,4-methylbenzaldehyde, 3,4-methylendioxybenzaldehyde,p-nitrobenzaldehyde, p-tolualdehyde, pyridine-4-aldehyde,pyridine-2-aldehyde, nonanal, acetoxyacetaldehyde, methyl or ethylpyruvate, ethyl α-ketobutyrate, diethyl mesoxalate,3,3-dimethoxypropanal, 3,3-di-n-butoxypropanal, succindialdehyde,adipaldehyde, 1,8-octanedial, 3-thiaglutaraldehyde 3,3-dioxide,homophthalaldehyde, dimethyl 1,6-hexanedial-3,4-dicarboxylate,o-phthalaldehyde, 3-oxaglutaraldehyde, methyl glyoxylate methanolhemiacetal, n-butyl glyoxylate methanol hemiacetal, n-ocyl glyoxalatemethanol hemiacetal, menthyl glyoxylate, borneyl glyoxylate, fenchylglyoxylate, 8-phenylmenthyl glyoxylate, 2-sulfobenzoic acid,4-nitro-2-sulfobenzoic acid, 4-nitro-2-sulfobenzaldehyde, 4-aminobenzoicacid, therephthalic acid, 2,3-pyridinedicarboxylic acids which areunsubstituted or substituted in position 4 and/or 5 and/or 6 byC₁-C₄-alkyl or alkoxy, C₁-C₄-alkyl-C₁C₄-alkoxy, halogen hydroxyl ornitro, 2-acetylnicotinic acid, nopinone, hydroxymethylpyridines, methyllactate, butyroxyacetaldehyde etc.

[0030] Suitable starting compounds for the ozonization are unsaturated,organic carbon compounds having one or more olefinic or aromatic doublebonds which can be cleaved off by ozone in the molecule.

[0031] These are, for example, unsaturated compound of the generalformula II

[0032] in which n is 0 or 1, Q₁ is hydrogen or the radicals

[0033] where R₁ is as defined above,

[0034] R₂ and R₃, independently of one another, are hydrogen, a C₁ toC₄-alkyl radical, a phenyl or pyridyl radical which is unsubstituted orsubstituted by groups which are inert under the reaction conditions, orare a —COOR₁ radical, or are a radical of the formula(CH₂)_(m)—O—CO—(CH₂)_(p), where m may be an integer from 1 to 4 and pmay be an integer from 1 to 6,

[0035] or, if n is 1 and Q₁ is the radical

[0036] R₂ and R₃ are together a single bond between two adjacent carbonatoms or are an alkylene radical having 2 to 4 carbon atoms if Y is ano-phenylene radical or an alkylene radical having 2 to 4 carbon atomsand R is a hydrogen atom, otherwise Y has the same meaning as X informula I, if n is 1, or if n is 0, is either hydrogen or, together withR₃ or with R₃ and the C═C double bond, is an optionally substituted,aliphatic, araliphatic, aromatic or heteroaromatic radical having 1 to50 carbon atoms which may be interrupted by oxygen, nitrogen or sulfur,or Y with R₃ and the C═C double bond is an optionally substituted mono-or bicyclic radical having 4 to 20 carbon atoms which can contain 1 or 2heteroatoms from the group S, N or O, or Y and R together form a mono-or bicyclic radical having 4 to 20 carbon atoms which can be mono- orpolysubstituted by groups which are inert under the reaction conditionsand R is as defined in formula I.

[0037] Suitable substituents are again C₁-C₂₀-alkyl or alkoxy oralkylalkoxy groups, such as, for example, methyl, ethyl, isopropyl,butyl, hexyl, octyl, decyl, dodecyl, methoxy, ethoxy, butoxy, hexoxymethoxymethyl, methoxyethyl, ethoxymetyl, ethoxyethyl, etc.; nitro,halogen, hydroxyl, CN, CONH₂, carboxyl, carboxylate, amino, SO₃H groups,etc.

[0038] As starting materials, it is accordingly possible to react thosecompounds of the formula II to give the corresponding monocarbonyl orbiscarbonyl or hydroxyl compounds of the formula I in which, forexample, Y is to be understood as meaning an aliphatic radical, forexample a divalent, straight-chain or branched alkylene radical having 1to 50, preferably 1 to 20, carbon atoms, where a CH₂ radical in thealiphatic chain may be replaced by oxygen, nitrogen, sulfur or by theSO₂ radical. Examples of an araliphatic radical are aralkylene,alkylarylene or alkylene-arylene radicals having, for example, 7-50,preferably 7-20, carbon atoms. An example of an aromatic radical is, forexample, a phenylene radical and an example of a heteroaromatic radicalis a divalent radical of a, for example, mono- or bicyclic heterocyclehaving one or two heteroatoms in the ring, where the rings arepreferably five- or six-membered. The abovementioned radicals can alsobe substituted by one or more groups which are inert under the reactionconditions, for example by alkyl, alkoxy or alkoxycarbonyl groups havingin each case 1 to 10 carbon atoms, preferably having 1 to 4 carbonatoms, or by nitro groups.

[0039] In a preferred manner, unsaturated compounds of the formula IIa

[0040] in which

[0041] R is defined as in formula I and R₃ is defined as in formula IIand

[0042] Y₁ and R₃ are identical and are both the radical—(CH₂)_(m)—O—CO—(CH₂)_(p) where m is 1 or 2 and p is 1, 2 or 3, or

[0043] Y₁ together with hydrogen, is a phenyl radical optionallysubstituted in the ortho and/or meta and/or para position or anoptionally substituted five- or six-membered heteroaryl radical with aheteroatom in the ring, but particularly preferably thepara-nitrophenyl, p-tolyl, 2- or 4-pyridinyl radical or, together withthe C═C double bond, is an optionally substituted mono- or bicyclicheterocycle, such as, for example, unsubstituted or substitutedquinoline or indole, or in which Y₁ and R together form a bicyclicradical having 4 to 10 carbon atoms which may be mono- orpolysubstituted by groups which are inert under the reaction conditions,are reacted to give the correspondingly preferred carbonyl or hydroxylcompounds.

[0044] Examples of unsaturated compounds of the formula IIa arebutenediol(1,4) dibutyrate, para-nitro- or para-methylstyrene, 2- or4-vinylpyridine, quinoline, 8-methylquinoline,3-ethyl-8-methylquinoline, indole, thiophene dioxide,stilbene-2,2′-disulfonic acid, 4,4′-dinitrostilbene-2,2′disulfonic acid,4,4′-vinylienedianiline, 4,4′-vinylenedipyridine,4,4′-stilbenedicarboxylic acid, β-pinene.

[0045] Preference is also given to reacting unsaturated compounds of theformula Iib

[0046] in which

[0047] R₄ is methyl or ethyl and R₅ is methyl, ethyl or theethoxycarbonyl radical, to give the correspondingly preferred carbonylcompounds. Very particular preference is given to reacting compounds inwhich R₄ and R₅ is methyl. Examples of starting compounds of the formulaIIb are methyl methacrylate, ethyl alkylacrylate or diethylmethylenemalonate. A further preferred group of starting materials forthe preparation of the correspondingly preferred carbonyl compounds ofthe formula I are compounds of the formula IIc

[0048] in which R₁ is as defined in formula I. Examples of compounds ofthe formula lic are 4,4-dimethoxybutene or 4,4-di-n-butoxybutene.

[0049] In addition, in a preferred manner, compounds of the formula IId

[0050] in which Y₂ is an o-phenylene radical or an alkylene radicalhaving 2 to 4 carbon atoms and R₆ and R₇ are together a single bondbetween the adjacent carbon atoms or an alkylene radical having 2 to 4carbon atoms, are reacted to give the correspondingly preferreddialdehydes of the formula I. Examples of compounds of the formula IIdare naphthalene or cyclooctadiene (1,5).

[0051] Finally, a further group of unsaturated compounds of the formulaIIe

[0052] in which

[0053] if R and R₃ are each H, Y₃ and R₈ are together an alkyleneradical having 2 to 6 carbon atoms or the radicals

[0054] —CH₂—SO₂—CH₂—, —CH₂—O—CH₂,

[0055] is reacted, in a preferred way, to give the correspondinglypreferred dialdehydes of the formula I, or if R and R₃ are each COOR₁and Y₃ and R₈ are H, to give the correspondingly preferred glyoxylicesters, their hemiacetals or monohydrates of the formula I.

[0056] Examples of compounds of the formula IIe are cyclohexene,cyclooctene, cyclododecene, sulfolene, indene, dimethyltetrahydrophthalate or 2,5-dihydrofuran, and also dimethyl or diethylmaleate, monophenylmenthyl maleate, monomenthyl, fenchyl or boneylmaleate, and the analogous fumaric esters.

[0057] Thus, for the process according to the invention a very widevariety of compounds are suitable, including those which may alsocontain complex structures with a very wide variety of functionalities.Thus, in addition to the preferred starting compounds already mentioned,compounds with complex structures, such as, for example, cephalosporinsetc. are also suitable as starting material. The only prerequisite orlimitation for choosing the reactant is the presence of at least onedouble bond which can be cleaved by ozone.

[0058] The ozonization according to the invention is carried out attemperatures of −80° C. to just below the explosion limit of the solventused, i.e. up to 100° C., depending on the solvent used. The temperatureis, again depending on the solvent used, −30 to +80° C., the maintenanceof a temperature of from −20 to +50° C. again being particularlypreferred. The ozonolysis can be carried out at atmospheric pressure orunder pressure.

[0059] The reaction of the unsaturated compounds with ozone in stage a)is carried out in an organic solvent in which the starting compounds arereadily soluble or in an aqueous solution.

[0060] Suitable organic solvents are, accordingly, alcohols, carboxylicacids, hydrocarbons etc. Preferred solvents are lower aliphatic alcoholshaving 1 to 6 carbon atoms, such as methanol, ethanol, isopropanol,etc., the use of methanol and ethanol being particularly preferred, ormixtures with nonhalogenated hydrocarbons.

[0061] In the preparation of, for example, glyoxylic ester hemiacetalsof the formula I, the alcohol used as solvent is important insofar asthis alcohol participates in the acetal formation. The ozonization stepcan, however, also be carried out in aqueous solution, depending on thereactant used. If the starting compound is itself insoluble in water,the salts thereof are used. In this connection, suitable salts are allthose which lead to water-soluble compounds. Examples thereof are alkalimetal or alkaline earth metal salts, such as, for example, sodium,potassium, calcium or magnesium salts. It is, however, also possible toprepare the aqueous solution of the corresponding salt of the startingcompound chosen by adding a suitable acid or base. Preferred acids aremineral acids, such as sulfuric acid, nitric acid or phosphoric acid.

[0062] The reaction with ozone takes place continuously according to theinvention, where ozone is used, depending on the reactivity of thereactants and substrates, relative to the solvent used, instoichiometric amounts up to a 40% excess. Preference is given to usingstoichiometric amounts up to a 20% excess of ozone.

[0063] In a first variant, equipment is used which consists of twoabsorption apparatuses, devices for dissipating the heat of thereaction, such as, for example, external or internal heat exchangers,and devices for separating the gas phase from the liquid phase.

[0064] The reactant streams here are countercurrent. The startingmaterial is fed into the first absorption apparatus, the startingconcentration depending on the reactant used and the reaction conditionsand preferably being between 1 and 3 mol/l, based on the double bonds,particularly preferably between 1.2 and 2 mol/l, based on the doublebonds; the ozone-bearing O₂ stream is, by contrast, introduced into thesecond absorption apparatus. The amount of ozone is chosen here,depending on the reactivity of the reactant, such that, for reactivesubstances, it preferably corresponds to a virtually stoichiometricozone consumption up to a about 107% of the stoichiometric amount and,for less reactive substances, an ozone consumption of about 107 to 140%,preferably up to 120%, of the stoichiometric amount based on thestarting compound.

[0065] In the first absorption apparatus, the reactant used is broughtinto contact with the ozone stream which, after passing through thesecond absorption apparatus, is fed into the first absorption apparatus.In this apparatus, there is a deficit of ozone since there are largeamounts of reactant present here, while the ozone content of theintroduced stream is reduced by up to 95%, depending on the substrateand nature of the column, as a result of being used up by the reactionin the second absorption apparatus. Following the reaction of the ozoneintroduced into the first absorption apparatus with the correspondinglyintroduced reactant, the reaction mixture emerges from the firstapparatus and is separated into a gas phase and a liquid phase.Virtually no ozone is present in the gas phase. The liquid phase, whichnow still comprises unreacted reactant, solvent and the correspondingozonolysis product, is then fed into the second absorption apparatusinto which, as has already been described above, the ozone-bearing O₂stream with the given starting concentration of ozone is introduced.There is thus an excess of ozone in this apparatus, based on thereactant, since only a small percentage of the amount of reactant, basedon the amount originally used, is present. The amount of reactant isaccordingly nearly only 1 to 10%, preferably 1 to 5% and particularlypreferably 1 to 3% of the starting concentration. In contrast, in thesecond absorption apparatus, large amounts of ozonolysis product,obtained by the reaction in the first absorption apparatus, are alreadypresent in the second absorption apparatus.

[0066] Surprisingly, the introduced ozone reacts, despite the lowconcentration of reactant and the high concentration of ozone product,more quickly with the residual amounts of reactant than with theozonolysis product or the solvent, meaning that, even at theseconcentration ratios, the high yield losses expected by the personskilled in the art do not actually arise.

[0067] When the reaction is complete, the reaction mixture emerges fromthe second absorption apparatus and is again separated into a gas phaseand a liquid phase. As described above, the gas phase contains only asmall percentage of ozone, which is introduced into the first apparatusfor further reaction of newly introduced reactant. The liquid phase,which now contains only the corresponding ozonolysis product in thesolvent used is then passed to the work-up stage (hydrogenation,oxidation or heating).

[0068] This variant is preferably used for reactants which react rapidlyrelative to the solvent or to the ozonolysis product formed.

[0069] In a further variant, the reactant stream is again fed into thefirst absorption apparatus. In this procedure, the ozone-bearing O₂stream is also introduced into the first apparatus, but some of thestream is also split off for the second apparatus and introduced into it(ozone split). The ozone-bearing O₂ stream is split here in a ratio offirst apparatus to second apparatus of from 50:50 to 90:10, preferablyfrom 70:30 to 85:15.

[0070] The O₂ stream introduced into apparatus 1 and 2 comprises about4-10%, preferably 5-8%, of ozone. Accordingly, in the first absorptionapparatus, there is again a deficit of ozone since large amounts ofreactant are present in this apparatus. The reactant concentration,based on the double bonds, after passing through the first absorptionapparatus, depends on the splitting ratio of the ozone stream and, for a50:50 split, is preferably 0.9 to 2 mol/l and particularly preferably 1to 1.5 mol/l and, for a 90:10 split, is preferably 0.1 mol/l to 0.5mol/l, particularly preferably 0.1 to 0.3 mol/l.

[0071] When the reaction is complete, the reaction mixture emerges fromthe first absorption apparatus and is separated into a gas phase and aliquid phase, the gas phase comprising only a small percentage of ozone.The liquid phase, which comprises mainly the corresponding ozonolysisproduct in the solvent used and residual, unreacted reactant in aconcentration of only 5 to 50%, preferably 10 to 50%, of the startingconcentration, is then introduced into the second absorption apparatus,where it is brought into contact with the ozone stream split off asdescribed above. In the second absorption apparatus, there is an excessof ozone since, as described, only small amounts of reactant pass intothe second apparatus. Despite ozonolysis product and solvent, whichactually have a high tendency to react with ozone, in essentially largeramounts compared with the reactant, the unreacted reactant neverthelessreacts with the introduced ozone.

[0072] When the reaction is complete, the reaction mixture emerges fromthe second absorption apparatus and is again separated into a gas phaseand a liquid phase. No or negligibly small amounts of ozone are presentin the gas phase. The liquid phase, which now comprises only thecorresponding ozonolysis product in the solvent used, is then passed tothe work-up phase (step b).

[0073] This variant is preferably used for substrates which reactslowly.

[0074] In one modification of this variant, the offgas from the firstabsorption apparatus can be mixed with the split-off partial stream, asresult of which it is diluted. In this case, an oxygen saving in thecase of the ozone-bearing O₂ stream is achieved. Furthermore, theoverall ozone consumption is somewhat reduced.

[0075] It is further possible to introduce only the offgas stream fromthe first absorption apparatus into the second apparatus and to dispensewith the splitting of the original ozone-bearing O₂ stream, meaning thatthe entire ozone-bearing O₂ stream is fed into the first apparatus. Thisresults both in a reduction in the ozone deficit in the first absorptionapparatus, and also in the ozone excess in the second apparatus.

[0076] In the case of very reactive reactants, it is also possible tocarry out the ozonization in only one step, i.e. in only one absorptionapparatus.

[0077] For all ozonization variants, it is also possible to replenishreactant with uninterrupted ozonization, as soon as the content ofreactant has dropped to a predetermined value, so that the content iskept constant at this value during the ozonization.

[0078] In the ozonization according to the invention, absorptionapparatuses are understood as meaning customary apparatuses which effecta gas-liquid exchange, such as, for example, absorption columns, bubblecolumns, stirred reactors, stirred-tank reactors, mixers, loop reactorsetc.

[0079] In a further preferred embodiment, the continuous ozonolysis iscarried out in two bubble columns as absorption apparatuses. The ozonestream can here be again passed countercurrently, as in the variant forrapidly reacting substrates, although the ozone-split is preferablyused.

[0080] The combination of bubble columns as absorption apparatuses andozone-split is particularly suitable for slowly reacting the substratesand for reactions in the aqueous system, for example for the ozonolysisof quinoline in the aqueous system.

[0081] The continuous ozonolysis according to the invention ischaracterized by its simple process control. Particular advantages arethat it does not result in ozone interruptions when changing batches,and the amount or concentration of ozone upon breakthrough, i.e. whenthe reaction is complete, can be readily controlled. As a result of thiscontinuous procedure, moreover, the amounts of peroxide in the reactionsolution are kept lower compared with the prior art. The reactionmixture leaving the circulation apparatus for the ozonolysis has aperoxide content of from 1 to 2 mol/l, preferably from 1 to 1.5 mol/l.

[0082] According to the invention, the continuous ozonolysis is followedby the work-up of the peroxide solution, which depends on the reactionconditions chosen during the ozonolysis. If the ozonolysis is carriedout in aqueous or mineral-acidic, aqueous solution, then the peroxidesobtained by the ozonolysis can be converted into the corresponding endproducts, for example, by simple heating. This is the case particularlyif substituted quinolines are converted into the correspondingsubstituted pyridinecarboxylic acids, such as, for example, into2-acetylnicotinic acid. Preference is given here to bubbling in oxygen,in the form of pure oxygen or in the form of air, at the same time, sothat the formation of secondary products is prevented.

[0083] In other cases, an oxidation step is necessary after theozonolysis in order to obtain the desired end-products. For thispurpose, the peroxide solution is treated with a suitable oxidizingagent, for example with hydrogen peroxide, hypochloride, peracids,peroxodisulfate, etc.

[0084] If stilbene compounds are used as starting materials, then amixture of corresponding aldehyde and hydroperoxide is present after theozonolysis. The peroxide can be decomposed either under acidicconditions or under alkali conditions. If the aldehyde is the desiredend-product, then this product is isolated from the mixture. If thecorresponding acid is the desired product, another oxidation step iscarried out.

[0085] If the ozonolysis is carried out not in aqueous solution, but inan organic solvent, then the ozonolysis is followed by continuoushydrogenation. In this connection, it is merely decisive that theperoxidic ozonolysis products are present in at least partiallydissolved form in an organic diluent which is inert under the reactionconditions of the hydrogenation. In addition to the solvents used in thenonaqueous ozonolysis, organic diluents are also to be understood asmeaning customary diluents used during the hydrogenation, such as, forexample, aliphatic or aromatic, optionally chlorinated, hydrocarbons,such as pentane, hexane, cyclohexane, toluene, xylene, methylenechloride, dichloroethane, chlorobenzenes, carboxylic esters, such asmethyl, ethyl or butyl acetates, ethers and ketones, provided they arenot able to form peroxides which are unacceptable from a safety viewpoint, and also alcohols, such as methanol, ethanol, isopropanol. Whenalcohols are used as diluents, the products which may form are not onlythe aldehydes or ketones corresponding to the olefins used, but alsotheir hemiacetals, acetals or their ketals, the acetalization orketalization essentially being dependent on the pH conditions.

[0086] In the process according to the invention, preference is given tousing peroxidic ozonolysis solutions in a lower, aliphatic alcoholhaving 1 to 6 carbon atoms, particularly preferably in methanol orethanol. However, surprisingly, the concentration of the peroxides inthe solution is not of importance for the process according to theinvention. In general, the solutions of the peroxidic ozonolysisproducts, which are obtained by the above-described, continuousozonolysis, have a peroxidic concentration of less than 2, preferably ofless than 1.5 mol/l. Since peroxides in relatively high concentrationshave a tendency for explosion-like decomposition, it is thereforepreferably to be observed that the solutions used have a peroxideconcentration below 2 mol/l, particularly preferably below 1.5 mol/l.

[0087] The catalytic hydrogenation of the ozonolysis product whichfollows the ozonization is carried out in the process according to theinvention in dilute solution, where, optionally with suitable measuresand devices therefor, care is taken that during the overallhydrogenation a peroxide content in the hydrogenation solution of below1.5 mol/l, preferably of below 1 mol/l, particularly preferably of below0.1 mol/l, very particularly preferably of at most 0.05 mol/l and inparticular of at most 0.02 mol/l is set and maintained.

[0088] To carry out the process in practice, a suspension of thecatalyst in the alcohol used in stage a) for the ozonization, preferablya methanol or ethanol, very preferably methanol, is introduced into ahydrogenation reactor, and the solution obtained during the ozonizationis continuously fed in by means of a controllable metering device. Whenadding the ozonolysis solution at the start and during the course of thehydrogenation, it is of course necessary to ensure that the peroxidecontent in the hydrogenation solution given above is not exceeded as aresult of the added amount of the peroxide-containing ozonizationproducts.

[0089] As a result of the low concentration of peroxide-containingozonization products during the actual hydrogenation operation, thequantitative ratio of catalyst to the substrate to be reduced isuniformly favorable through the entire duration of the hydrogenation,meaning that even when the catalyst is used sparingly, a rapid reductionis ensured. In this way, the poisoning which is otherwise observed athigh peroxide concentrations, and the loss in activity of the catalystassociated therewith is also prevented.

[0090] Viewed overall, however, as a result of the continuous feed, alarge amount of ozonization products can be reductively cleaved in arelatively small volume, as a result of which, in the end stage of theprocess, concentrated solutions form and, as well as solvent itself,time and costs for the distillative removal of the solvent duringwork-up can be saved. Suitable catalysts are the noble metal catalystscustomarily used for hydrogenations, which can be used in the form ofpowder catalysts with support material or without support material.Preference is given to using palladium or platinum catalysts, inparticular platinum catalysts without support material. In the case ofpowder catalysts, suitable support materials are, for example, carbon,aluminum, silica gel or kieselguhr. It is also possible to use monolithcatalysts. A monolith catalyst is to be understood as meaning a catalystwhich consists of a support coated with a catalyst base material. Thesupport preferably has as large a surface area as possible, which can beachieved, for example, by honeycomb or lamellar structuring. The supportis in the form of one piece and can consist of materials suitable forthis purpose, for example of metal, glass, ceramic, plastic. Preferenceis given to a metal support, for example made of steel, aluminum, sinceit has been found that this uniformly absorb the heat of the reactionand dissipate it again into the surrounding reaction medium. This isbecause it has been found that the use of nonconductive materials assupport may lead to local overheating in the reaction medium, meaningthat yields and purity of the reaction products can be impaired.Catalyst base substance is to be understood as meaning catalyst basesubstances which are customary for the reduction of organic peroxidesolutions. Examples of customary catalysts base substances are noblemetals, such as platinum, palladium, transition metals, such as nickel,cobalt, rhodium, the oxides thereof, or mixtures of such metals or metaloxides. In this connection, these metals can be partially poisoned byheavy metals such as lead, bismuth. In the process according to theinvention, preference is given to using noble metals or mixtures ofnoble metals with transition metals as catalyst base substance. In theprocess according to the invention, the yields are per se independent ofthe amount of catalyst used, although it is recommended, to achieve asufficient hydrogenation rate, to initially introduce said catalysts innoble metal amounts of from 0.1 to 5% by weight, preferably from 0.5 to2% by weight, based on the total amount of ozonization productsintroduced in each case per hour.

[0091] In the process according to the invention, equivalent amounts ofhydrogen are consumed for the reduction of the ozonization products. Theamount of hydrogen which can be used during the hydrogenation rangesfrom one mole equivalent to a manifold molar excess. The use of excesshydrogen does not afford any advantages and is only expedient in orderto ensure an adequate supply of hydrogen to the hydrogenation mixture.

[0092] In the process according to the invention, the hydrogenation canbe carried out under virtually pressureless conditions. Virtuallypressureless conditions are to be understood here as meaning pressuresof from 1 to about 3 bar, as is customary in the art, in order toprevent the penetration of air into the hydrogenation reactor. In thisway, the reduction of the ozonization products can be carried out verysimply in technical and apparatus terms. It is, however, also possibleto carry out the hydrogenation at a pressure up to 20 bar, therebyincreasing the rate of hydrogenation.

[0093] The reductive cleavage generally proceeds exothermically and iscarried out at temperatures of from −10 to +150° C., depending on theproduct, and according to a preferred embodiment of the presentinvention at +15 to +70° C. and particularly preferably at temperaturesin the range from +20 to +50° C.

[0094] Preference is given to maintaining a pH of from 2 to 5 during thehydrogenation. Since acidic secondary products can form in small amountsduring the course of the hydrogenation, a base, preferably dilute sodiumhydroxide solution, may optionally be added in a metered way to maintainthe desired pH.

[0095] When the hydrogenation is complete, under the conditions of theprocess according to the invention, a preferably alcoholic solution ofthe process products is obtained, which is virtually peroxide-free andcan be worked-up in a risk-free manner.

[0096] For the continuous hydrogenation according to the invention, allhydrogenation reactors which ensure adequate mass transfer of hydrogeninto the liquid phase are suitable. These may, for example, have tubularreactors of very diverse construction, such as, for example,stirred-tank reactors, loop reactors, etc. Suitable stirrers, such as,for example, 3-paddle stirrers, injectors etc. It is, however, alsopossible to use stirred or unstirred bubble columns, fixed-bed reactorsetc.

[0097] In the process according to the invention, in one variant theperoxide-containing ozonolysis product solution obtained from theozonolysis stage, and the stream of hydrogen is passed into thehydrogenation apparatus. The hydrogenation apparatus consists here, forexample, of a stirred reactor, fitted with a 3-paddle stirrer, hydrogeninlet, hydrogen measurement, pH measurement, temperature measurement,cooling, filtration device and metering pumps. The desired solvent andthe catalyst used, preferably no monolith catalyst, are initiallyintroduced. The peroxide solution is then fed in with stirring,preferably with vigorous stirring with the continuous introduction ofhydrogen gas. The desired peroxide content can be regulated via thedosing rate. Where appropriate, the addition of a base for regulatingthe pH can be carried out simultaneously. The volume of the reactionsolution is kept constant by level-adjusted discharge via the filtrationunit, where the peroxide content of the discharged solution iscontinually monitored. The peroxide content of the separated-offsolution is here below 0.01 mo/l. In contrast to the prior art, it isnot necessary here to separate off the catalyst since the catalyst, if asuitable filtration unit is chosen, is not discharged with the productsolution, but is again returned to the reaction vessel. Particularlysuitable filtration units are, accordingly, cross-flow filtrationapparatuses which are equipped, for example, with metal frits in theform of sintering tubes, or immersed metal frits.

[0098] As a result of the process control according to the invention, itis thus possible to use the catalyst for years since chemical poisoningdoes not occur. Only mechanical wear becomes noticeable upon use foryears. In addition, the peroxides are reacted rapidly and reliably.

[0099] Step b) can be carried out continuously or else discontinuously.

EXAMPLE 1 Comparative Example A: Batch

[0100] a) Ozonization:

[0101] A continuous circulation apparatus consisting of an absorptioncolumn, separation vessel, recirculation pump and external heatexchanger was charged with 4 liters of a methanolic solution of 900 g ofDMM (content of 225 g/l, corresponding to 1.56 mol/l). The temperaturewas cooled to −20° C. by cooling via the external heat exchanger. Therecycle amount was about 220 l/h.

[0102] The solution was brought into contact with 2500 l/h (STP) ofozone/oxygen stream with an ozone content of 55 g/Nm³ in the absorptioncolumn and reacted with the ozone present. The exothermic reaction tookplace virtually immediately, and all of the ozone was taken up. In theseparation vessel at the foot of the absorption column, the mixtureseparated into a liquid phase and a gas phase.

[0103] When the ozonolysis was complete, the DMM content was about 2g/l, corresponding to 1% of the starting amount.

[0104] The amount of ozone taken up was determined and was overall about305 g, corresponding to 102% of theory.

[0105] b) Hydrogenation:

[0106] The solution obtained in the ozonolysis was divided into portionsand was fed, via a dosing vessel, into a hydrogenation reactor intowhich a suspension of 1.5 g of Pt Adams catalyst, prepared byhydrogenation of PtO₂, in 0.5 liter of methanol had been introduced andwhich had been filled with hydrogen, in doses such that the peroxidecontent in the hydrogenation reactor at the start and over the course ofthe entire hydrogenation was at most 0.1 mol/l. Hydrogenation wascontinued with vigorous stirring and the addition of hydrogen until theperoxide sample was negative, a temperature of 30° C.-33° C. and, byadding methanolic NaOH, a pH of from 2 to 4 being maintained over theentire hydrogenation period.

[0107] The contents of the hydrogenation reactor were then drawn offwith suction via a frit until the residue was 0.5 liters, solutionozonized afresh was fed into the reactor via the metering vessel, andthe hydrogenation operation was repeated under the reaction conditionsgiven above.

[0108] When the hydrogenation was complete, a polarographicallydetermined methyl glyoxylate-methanol hemiacetal content of 12.125 mol(97% of theory) was established. For work-up, NaOH present in bondedform in the hydrogenation mixture was carefully precipitated out bycooling with 98% strength H₂SO₄ as Na₂SO₄ and separated off byfiltration. The methanol was then removed on a rotary evaporator and theresidue was distilled at about 55° C. and 25 Torr. The yield of puremethyl glyoxylate-methanol hemiacetal was 1425 g (11.87 mol),corresponding to 95% of theory.

EXAMPLE 2

[0109] a) Ozonization:

[0110] 4 liters of methanolic DMM solution were ozonized as described inExample 1 in the recirculation apparatus from Example 1. As soon as theDMM content had dropped to 2 g/liter, further DMM solution was fed in,with uninterrupted O₃ introduction, at the same concentration as inExample 1 such that the DMM content was kept constant between 2 and 3g/liter. In this way, a total of 16 liters of methanolic peroxidesolution were obtained, 3600 g of DMM were ozonized.

[0111] The total amount of ozone taken up was 1450 g, corresponding to30.25 mol=121% of theory. The ozone consumption is significantly greatercompared with Example 1, ozone was consumed in the secondary reactions.

[0112] b) Hydrogenation:

[0113] The solution obtained in the ozonolysis was fed, via a meteringvessel, into a hydrogenation reaction into which a suspension of 1.5 gof Pt in 0.5 liter of methanol had been introduced and which had beenfilled with hydrogen, at a metering rate such that the peroxide contentin the hydrogenation reactor at the start and over the course of theentire hydrogenation was at most 0.01 mol/l. The consumed hydrogen wascontinually topped up by means of pressure regulation. Here, over theentire hydrogenation period, a temperature of 30° C.-33° C. wasmaintained by cooling, and a pH of from 2 to 3 was maintained by addingmethanolic NaOH. As soon as the hydrogenation reactor was full,hydrogenated solution was continuously taken off via an immersed frit inorder to keep the level virtually constant. During this, the meteredaddition of the peroxide solution was not interrupted. The peroxidecontent was controlled continually by iodometric titration. When thehydrogenation was complete, the hydrogenation reactor was emptied viathe frit and a polarographically determined methyl glyoxylate-methanolhemiacetal content of 5100 g=42.5 mol (85% of theory) was established.

EXAMPLE 3

[0114] a) Ozonization:

[0115] In a recirculation apparatus as described in Example 1, 16 litersof a solution of 3600 g of DMM in methanol were ozonized in 4 parts eachof 4 liters until the DMM content had dropped to about 40 g/l. Theperoxide solution obtained in this way was stored in a deep-freeze atabout −30° C. During storage, neither an exothermic reaction nor adecrease in the peroxide content was established.

[0116] In the second stage of the ozonization, the stored peroxidesolution was ozonized analogously to Example 2 to a DMM content of 2-3g/l. In this way, a total of 16 liters of methanolic peroxide solutionwere obtained, and 3600 g of DMM were ozonized. The total amount ofozone taken up was 1252 g, corresponding to 26.1 mol=104% of theory.

[0117] b) Hydrogenation:

[0118] The solution obtained in the ozonolysis was fed, via a meteringvessel, into a hydrogenation reactor into which a suspension of 1.5 g ofPt in 0.5 liter of methanol had been introduced and which had beenfilled with hydrogen, at a metering rate such that the peroxide contentin the hydrogenation reactor at the start and over the course of theentire hydrogenation was at most 0.01 mol/l. The consumed hydrogen wascontinually topped up by means of pressure regulation. Here, over theentire hydrogenation period, a temperature of 30° C.-33° C. wasmaintained by cooling, and a pH of from 2 to 3 was maintained by addingmethanolic NaOH. As soon as the hydrogenation reactor had been filled,hydrogenated solution was drawn off continuously via an immersed frit inorder to keep the level virtually constant. During this, the meteredaddition of the peroxide solution was not interrupted. The peroxidecontent was continually controlled by iodometric titration.

[0119] When the hydrogenation was complete, the hydrogenation reactorwas emptied via the frit, and a polarographically determined methylglyoxylate-methanol hemiacetal content of 48 mol (96% of theory) wasestablished.

EXAMPLE 4

[0120] a) Ozonization:

[0121] In a recirculation apparatus as described in Example 3, 16 litersof a solution of 3600 g of DMM in methanol were ozonized, although thistime until the DMM content had dropped to about 120 g/l. The peroxidesolution obtained in this way was stored in a deep-freeze at about −30°C. During storage, neither an exothermic reaction nor a decrease in theperoxide content was established.

[0122] In the second stage of the ozonization, the stored peroxidesolution was ozonized analogously to Example 2 to a DMM content of 2-3g/l. In this way, a total of 16 liters of methanolic peroxide solutionwere obtained, and 3600 g of DMM were ozonized. The total amount ofozone taken up was 1288 g, corresponding to 26.8 mol=107% of theory.

[0123] b) Hydrogenation:

[0124] The solution obtained in the ozonolysis was fed, via a meteringvessel, into a hydrogenation reactor into which a suspension of 1.5 g ofPt in 0.5 liter of methanol had been introduced and which had beenfilled with hydrogen, at a metering rate such that the peroxide contentin the hydrogenation reactor at the start and over the course of theentire hydrogenation was at most 0.01 mol/l. The consumed hydrogen wascontinually topped up by means of pressure regulation. Here, over theentire hydrogenation period, a temperature of 30° C.-33° C. wasmaintained by cooling, and a pH of from 2 to 3 was maintained by addingmethanolic NaOH. As soon as the hydrogenation reactor had been filled,hydrogenated solution was drawn off continuously via an immersed frit inorder to keep the level virtually constant. During this, the meteredaddition of the peroxide solution was not interrupted. The peroxidecontent was continually controlled by iodometric titration.

[0125] When the hydrogenation was complete, the hydrogenation reactorwas emptied via the frit, and a polarographically determined methylglyoxylate-methanol hemiacetal content of 2748 g=47.9 mol (95.8% theory)was established.

EXAMPLE 5

[0126] a) Ozonization:

[0127] In a recirculation apparatus as described in Example 3, 4 litersof a solution of 900 g of DMM in methanol were ozonized, until the DMMcontent had dropped to about 40 g/l. Then, with uniform feed of ozone, afurther 20 l of a solution with a cencentration of 225 g/l were meteredin such a way that a DMM content of 40 g±2 g/l was retained in theozonolysis solution. The level in the apparatus was kept constant bywithdrawing the excess peroxide solution produced. The peroxide solutionobtained in this way was stored in a deep freeze at about −30° C. Duringstorage, neither an exothermic reaction nor a decrease in the peroxidecontent was established.

[0128] In the second stage of the ozonization, the stored peroxidesolution was ozonized analogously to Example 2 to a DMM content of 2-3g/l. In this way, a total of 24 liters of methanolic peroxide solutionwere obtained, and 5400 g of DMM were ozonized. The total amount ofozone taken up was 1900 g, corresponding to 39.6 mol=106% of theory.

[0129] b) The hydrogenation was carried out as in Example 4.

[0130] When the hydrogenation was complete, the hydrogenation reactorwas emptied by the frit and a polarographically determined methylglyoxylate-methanol hemiacetal content of 8640 g (yield 96.0% of theory)was established.

EXAMPLE 6 Comparative Example B: Ozonolysis Batch Hydrogenation cont.

[0131] a) Ozonization:

[0132] A peroxide solution was prepared by ozonolysis of naphthalene inmethanol analogously to Example 1. For this, 256 g of naphthalene wereozonized in 4 liters of methanolic solution. The initially undissolvednaphthalene dissolved over the course of the ozonization.

[0133] b) Hydrogenation:

[0134] The solution obtained in the ozonolysis was fed, via a meteringvessel, into a hydrogenation reactor into which a suspension of 1.5 g ofPt in 0.5 liter of methanol had been introduced and which had beenfilled with hydrogen, at a metering rate such that the peroxide contentin the hydrogenation reactor at the start and over the course of theentire hydrogenation was at most 0.01 mol/l. The hydrogen consumed wascontinually topped up by means of pressure regulation. During this, overthe entire hydrogenation period, a temperature of 30° C.±2° C. wasmaintained by cooling, and a pH of from 2 to 4 was maintained by addingmethanolic NaOH. As soon as the hydrogenation reactor was full, solutionhydrogenated continuously was taken off via an immersed frit in order tokeep the level virtually constant. During this, the metered addition ofthe peroxide solution was not interrupted.

[0135] When the hydrogenation was complete, a content ofortho-phthalaldehyde of 220.5 g (82.3% of theory) was established. Thesolution was set at pH 1 for work-up with H₂SO₄. After 4 hours, theacetalization was complete. The methanolic acetal solution was addeddropwise to an excess hydroxide solution, and the methanol was distilledoff simultaneously. The acetal was extracted twice from the reactionmixture using MTBE, and the solvent was removed on a rotary evaporator.This left a residue of phthalaldehyde-dimethylacetal. The weight was293.3 g, corresponding to 81.5% of theory.

EXAMPLE 7

[0136] a) Ozonization:

[0137] In the recirculation apparatus from Example 1, 4 liters of 0.5molar methanolic naphthalene solution were ozonized as described inExample 2. As soon as the naphthalene content had dropped to 2 g/l, afurther 0.5 mol of naphthalene solution was fed in, with uninterruptedO₃ introduction, so that the naphthalene content was kept constantbetween 2 and 3 g/liter. In this way, a total of 8 liters of methanolicperoxide solution were obtained, and 512 g of naphthalene were ozonized.

[0138] The total amount of ozone taken up was 495 g, corresponding to10.31 mol=129% of theory.

[0139] b) Hydrogenation:

[0140] The hydrogenation was carried out continuously as in Example 6.When the hydrogenation was complete, a content of ortho-phthalaldehydeof 160.7 g (60% of theory) was established by GC.

EXAMPLE 8

[0141] a) Ozonization:

[0142] In a recirculation apparatus as described in Example 3, 8 litersof a solution of 512 g of naphthalene in methanol were ozonized untilthe naphthalene content had dropped to about 20 g/l. The peroxidesolution obtained in this way was stored in a deep-freeze at about −30°C. During storage, neither an exothermic reaction nor a decrease in theperoxide content was established.

[0143] In the second stage of the ozonization, the stored peroxidesolution was ozonized analogously to Example 2 to a naphthalene contentof 2-3 g/l. In this way, a total of 8 liters of methanolic peroxidesolution were obtained.

[0144] The total amount of ozone taken up was 458 g, corresponding to9.54 mol=119% of theory.

[0145] b) Hydrogenation:

[0146] The hydrogenation was carried out continuously as in Example 6.When the hydrogenation was complete, a content of ortho-phthalaldehydeof 417.9 g (78% of theory) was established.

EXAMPLE 9 Comparative Example C

[0147] 4 liters of a solution of 600 g of methyl methacrylate inmethanol with an addition of 0.1 g of hydroquinone to preventpolymerization, were ozonized as in Example 2 to an MMA content of 1 g/land then hydrogenated with a Lindlar catalyst 5% Pd/Pb on CaCO₃ at pH 5.Some of the methyl methacrylate used was discharged during theozonolysis by the O₂ off gas. The ozone consumption was, at 266 g, only92% of theory. Following the hydrogenation, the methyl pyruvate presentin the solution was determined as 528 g, corresponding to 86.3% oftheory, based on methyl methacrylate used.

EXAMPLE 10

[0148] In a recirculation apparatus, a minimal volume of 1.5 l ofmethanol with a concentration of 2 g/l of methyl methacrylate wasinitially introduced, and the ozonization and the metered addition of 4liters of an MMA solution of concentration 150 g/l were startedsimultaneously, such that the methyl methacrylate (MMA) content remainedconstant roughly in the range 1 g/l±1 g/l.

[0149] A total of 603 g of methyl methacrylate were ozonized, and theozone consumption was 283 (98% of theory).

[0150] The hydrogenation was carried out analogously to Example 9. Inthe hydrogenation solution, 567.8 g of methyl pyruvate were found.(92.8% of theory)

EXAMPLE 11

[0151] In a recirculation apparatus, a minimal volume of 1.5 l ofmethanol with a concentration of 20 g/l of methyl methacrylate wasinitially introduced, and the ozonization and the metered addition of 8liters of an MMA solution of concentration 150 g/l were startedsimultaneously, so that the MMA content remained constant roughly in therange 20 g/l±1 g/l. The peroxide solution resulting from the ozonolysiswas stored at −30° C. for the second stage of the ozonolysis. In thesecond stage of the ozonolysis, 1.5 l of peroxide solution from Stage 1were initially introduced and ozonized to a concentration of about 1 g/lof methyl methacrylate. Then, with continuing ozonolysis, the peroxidesolution from Stage 1 was metered in so that the concentration of methylmethacrylate was kept constant at 1 g/l±1 g. The peroxide solution waswithdrawn continuously from the apparatus so that the level of solutionin the apparatus remained approximately constant.

[0152] A total of 1230 g of methyl methacrylate was ozonized, and theozone consumption was 562 (95% of theory)

[0153] The hydrogenation was carried out analogously to Example 9. Inthe hydrogenation solution, 1148 g of methyl pyruvate were found. (91.5%of theory, based on methyl methacrylate used).

EXAMPLE 12 Comparative Example D

[0154] Methyl methacrylate was ozonized as in Example 9 and continuouslyhydrogenated, although the catalyst used was platinum sponge, obtainedby hydrogenation of 3 g of PtO₂. The hydrogenation was carried out as inExample 9 at pH 5. Inclusive of the rinse solutions, 4.6 liters of amethanolic solution were obtained, which comprised 549 g of methyllactate. (88.1% of theory based on methyl methacrylate and 95.7% basedon ozone used).

EXAMPLE 13

[0155] 4 liters of a solution of 600 g of methyl methacrylate wereozonized analogously to Example 10 and hydrogenated as in Example 12. Inthe hydrogenation solution, 580 g of methyl lactate (93% of theory basedon methyl methacrylate used) were found.

EXAMPLE 14 Comparative Example E

[0156] 4 liters of a solution of 440 g of cyclooctene in methanol wereozonized as in Example 1. Immediately at the start of the ozonolysisthere was considerable mist formation in the offgas. The mist formationwas largely independent of the zone concentration, but did not arisewhen pure oxygen without ozone was used. The ozonolysis was interruptedfor reasons of safety and the apparatus was emptied and cleaned.

EXAMPLE 15

[0157] 4 liters of a solution of 440 g of cyclooctene (4 mol) inmethanol were prepared. As described in Example 10, 1.5 liters ofmethanol were initially introduced, and 30 ml of cyclooctene solutionwere metered in, giving about 2 g/l of cyclooctene. The metered additionwas stopped and then the ozonization was started with the simultaneousmetered addition of cyclooctene solution. Sufficient cyclooctene wasmetered in for a cyclooctene concentration of 2 g/l±1 g/l to bemaintained in the ozonolysis solution. Mist formation in the offgas wasnot observed at this concentration. The ozone consumption was 92 g (96of theory).

[0158] The peroxide solution was continuously hydrogenated as in Example2. 5.2 liters of a methanolic solution containing 522 g of octanedial(92% of theory, based on cyclooctene used) were obtained. The solutionwas adjusted to pH 1 with sulfuric acid, left to stand overnight at roomtemperature and adjusted to pH 10 with NaOH. 1 liter of water was thenadded, and the methanol was removed at a water-bath temperature of 100°C. using a rotary evaporator. The organic phase was separated off fromthe two-phase residue, the aqueous phase was extracted with 1×100 ml ofMTBE, the organic phase was combined, dried with Na₂SO₄ and fractionatedunder reduced pressure. 855 g of 1,1,8,8-tetramethoxyoctane ofKp₃₀=147-149° C. were obtained (91% of theory).

EXAMPLE 16

[0159] 4 liters of a solution of 417 g (4 mol) of vinylpyridine inmethanol were ozonized analogously to Example 15, a concentration ofabout 2 g of vinylpyridine per liter being maintained by continuouslymetering in vinylpyridine solution in the ozonolysis. At thisconcentration, the uptake of ozone is still quantitative. The uptake ofozone is 196 g (102% of theory). The hydrogenation was carried outbatchwise without pH regulation at 20° C. over 4 g of 10% Pd catalyst onactivated carbon as described in Example 1. The product solution wasanalyzed by gas chromatography and the yield of pyridine aldehyde wasdetermined as 347 g (81% of theory).

EXAMPLE 17

[0160] 8 liters of a solution of 834 g of vinylpyridine in methanol wereozonized in a first stage as in Example 11 continuously at avinylpyridine concentration of 20 g/l, and in a second stage at avinylpyridine concentration of 2 g/l. The uptake of ozone is 380 g(98.9% of theory). The peroxide solution obtained was hydrogenatedcontinuously without pH check at a maximum of 20° C. over 4 g of 10% pHcatalyst on activated carbon. The product solution was analyzed by gaschromatography and the yield of pyridine aldehyde was determined as 720g (84% of theory).

EXAMPLE 18

[0161] 4 liters of a solution of 417 g (4 mol) of vinylpyridine inmethanol were ozonized analogously to Example 16 and hydrogenated with 4g of 10% Pd catalyst on activated carbon at at least 40±2° C. batchwisewithout the addition of hydroxide solution. The consumption of ozone was196 g (102% of theory). The ozonized solution was fed into the hydrogenapparatus so that a peroxide content of 10 mmol was not exceeded. Thepyridinealdehyde concentration formed in the process was less than 1%.The hydrogenated product solution was slowly introduced into excessaqueous sodium hydroxide solution, and the methanol was distilled off atthe same time. In this step, pyridinealdehyde obtained in thehydrogenation was disproportionated to give hydroxymethylpyridine (HMP),and the simultaneously formed formaldehyde was disproportionated to giveformate and methanol. The HMP was extracted from the resulting alkalinereaction mixture with 10×MTBE, the MTBE was distilled off from theorganic phases, and the residue was fractionated at 80 mbar and 143° C.332.1 g (76% of theory) of pure HMP were obtained as a colorless liquid.

EXAMPLE 19

[0162] 12 liters of a solution of 1250 [lacuna] of vinylpyridine (12mol) in methanol were prepared, and a 1 molar solution of vinylpyridinein methanol was ozonized analogously to Example 3, a concentration of 20g of vinylpyridine per liter being maintained in the ozonolysis bymetered addition. A total of 12 l of solution and thus 12 mol ofvinylpyridine were fed in. All of the ozone introduced was taken up. Theresulting peroxide solution was stored in a deep-freeze at −30° C. andused for a further continuous ozonolysis at a vinylpyridine content ofabout 2 g/l. The total ozone consumption was, at 570 g or 98.9% oftheory, somewhat lower than in Example 18. The resulting peroxidesolution was hydrogenated analogously to Example 17. After work-upanalogously to Example 18, 1024 [lacuna] (78.1% of theory) ofhydroxymethylpyridine were obtained.

EXAMPLE 20 Comparative Experiment F

[0163] 4 liters of a solution of 220 g of cyclooctene in methanol wereozonized as in Example 1. Immediately at the start of the ozonolysisthere was considerable mist formation in the offgas. The mist formationwas largely independent of the ozone concentration, but did not arisewhen pure oxygen without ozone was used. The ozonolysis was interruptedas in Example 14 for reasons of safety and the apparatus was emptied andcleaned.

EXAMPLE 21

[0164] 4 liters of a solution of 220 g of cyclooctene (4.07 mol) inmethanol were prepared. The ozonization was carried out as described inExample 15, a maximum concentration of 2 g of cyclooctadiene beingmaintained in the ozonolysis solution. Mist formation in the offgas wasnot observed at this concentration. The ozone consumption was 190 g(97.3 of theory).

[0165] The peroxide solution was hydrogenated continuously as in Example15. 5.2 liters of a methanolic solution were obtained. The overall yieldwas determined by oxime titration and revealed 330 g of succindialdehyde(94.3% of theory).

[0166] Characterization: the solution was treated with the molar amountof trimethylorthoformate, adjusted to pH 1 with sulfuric acid, left tostand overnight at room temperature and adjusted to pH 10 with NaOH. 1liter of water was then added, and the methanol was removed at awater-bath temperature of 100° C. using a rotary evaporator. The organicphase was separated off from the two-phase residue, the aqueous phasewas extracted with 3×100 ml of MTBE, the organic phase was combined,dried with Na₂SO₄ and fractionated under reduced pressure at 15 mbar.486.5 g of 1,1,4,4-tetramethoxybutane of Kp₁₅=86-88° C. were obtained(90.5% of theory).

EXAMPLE 22 Comparison G

[0167] In a small-scale experiment, 1 molar solution of pinene inmethanol was prepared and ozonized. Immediately at the start of theozonolysis, mist formation arose in the offgas and the experiment wasinterrupted. The ozonization solution was diluted until mist formationwas no longer observed. The adjusted concentration of pinene was about28 g/l (=0.21 mol/l).

EXAMPLE 23

[0168] 4 liters of a solution of 400 g of pinene in methanol wereozonized as in Example 15 with 130 g of ozone (92.3% of theory) andcontinuously hydrogenated at 30° C. and pH 4.5. The nopinone content inthe hydrogenation solution was determined by gas chromatography as 363 g(89.6% of theory, based on pinene used). The hydrogen solution wastreated with 1 of water, adjusted to pH 5 with H₂SO₄, and the methanolwas distilled off over a column. The resulting two-phase mixturecomprised small fractions of a solid having an exothermic potential ofabout 1200 J/g. The mixture was therefore distilled with steam until thedistillate was single-phase and the nopinone content in the distillatehad dropped to below 2 g/l. The distillate was extracted with 2×MTBE,and the combined organic phases were fractionated. 356 g (87.6% oftheory, based on pinene used) of pure nopinone were obtained.

EXAMPLE 24

[0169] 4 liters of a solution of 900 g of butenediol (1,4) dibutyrate(3.94 mol) in methanol were ozonized as in Example 15 with 191 g ofozone (101% of theory) and continuously hydrogenated at 30° C. and pH3.5. In the hydrogenation solution, the content of butyroxyacetaldehydewas determined as 933.8 g (91.0% of theory).

EXAMPLE 25 Comparative Example H

[0170] 4 liters of a methanolic solution of 470 g of sulfolene wereozonized as in Example 1 to a sulfolene content of <2 g/l and thenhydrogenated as in Example 2 with 2 g of Adams catalyst at pH 3.5. Theozone consumption was, at 189 g, 99% of theory. After the catalyst hadbeen separated off, the oxime titration revealed a content of 568 g of3-thiaglutaraldehyde 3,3-dioxide (95.1% of theory).

EXAMPLE 26

[0171] 8 liters of a methanolic solution of 940 g of sulfolene wereozonized as in Example 15 to a sulfolene content of <2 g/l and thenhydrogenated continuously as in the same example with 2 g of Adamscatalyst at pH 3.5. The ozone consumption was with 388 g (101.6% oftheory) and is thus somewhat higher than in Example 25.

[0172] After the catalyst has been separated off, the oxime titrationreveals a content of 1140 g of 3-thiaglutaraldehyde 3,3-dioxide (94.8%of theory).

EXAMPLE 27 Comparative Example I

[0173] 4 liters of a solution of 300 g of 2,5-dihydrofuran (4.28 mol) inmethanol were ozonized as in Example 1 with 163 g of ozone (79% oftheory) and hydrogenated continuously at 30° C. and pH 3.5. Some of thedihydrofuran was discharged during the ozonolysis with the offgasstream.

[0174] In the hydrogenation solution, the content of 3-oxaglutaraldehydewas determined by oxime titration as 321 g (73.5% of theory).

EXAMPLE 28

[0175] 8 liters of a solution of 600 g of 2,5-dihydrofuran (4.28 mol) inmethanol were ozonized as in Example 2 with 398 g of ozone (96.9% oftheory) and hydrogenated continuously at 30° C. and pH 3.5. The contentof dihydrofuran in the offgas was below 2% of the feed amount.

[0176] In the hydrogenation solution, the content of 3-oxaglutaraldehydewas determined by oxime titration as 833 g (95.3% of theory).

EXAMPLE 29 Comparative Experiment PDC Batch in Recirculation Apparatus

[0177] Ozonization:

[0178] 4 g of an aqueous solution of 240 g of quinoline (6% by weight,corresponding to 0.464 mol/kg) and 330 g of conc. sulfuric acid areintroduced into a continuous recirculation apparatus, consisting of anabsorption column, separation vessel, recirculation pump and externalheat exchanger. The temperature is cooled to 0 to +3° C. by cooling viathe external heat exchanger. The amount recirculated is about 220 l/h.

[0179] The solution is brought into contact with 2500 l/h (STP) of anozone/oxygen stream with an ozone content of 96 g/Nm³ in the absorptioncolumn and reacted with the ozone present. All of the ozone is not takenup. The concentration of unreacted ozone in the offgas was 26 g/Nm³ atthe start of the batch (corresponding to 27% of unreacted ozone) and 61g/Nm³ at the end of the batch (corresponding to 63.5% of unreactedozone). In the separation vessel at the foot of the absorption column,the mixture separates into a liquid phase and a gas phase.

[0180] When the ozonolysis is complete, the quinoline content is about0.7 g/l, corresponding to 1.1% of the starting amount.

[0181] The amount of ozone taken up was determined and was about 194 goverall, corresponding to 111% of theory.

[0182] Oxidation:

[0183] The solution obtained in the ozonolysis is treated, at 2 to 5°C., with 210 g of 30% H₂O₂ cooled to +5° C. As a result of the heat ofthe reaction, the temperature increases slowly and is maintained below20° C. by cooling. PDC begins to crystallize even during the reaction.After 8 hours the reaction is complete.

[0184] The pH is adjusted to 1.5 and the reaction mixture is cooled to0° C.

[0185] The precipitated PDC is filtered over a suction filter, washedwith methanol and dried under reduced pressure at 40° C. to a constantweight. The yield of crystallized PDC is 217 g, corresponding to 71% oftheory, and a further 30 g are present in the mother liquor. The motherliquor is evaporated to one third of its volume under reduced pressure.After cooling to 0° C., filtration and drying, a further 24 g of PDC (8%of theory) are obtained. The yield of isolated PDC is thus 241 g (79% oftheory), calculated based on quinoline. Total yield 247 g (81%).

EXAMPLE 30 PDC Continuously in Two Bubble Columns with Ozone Split

[0186] Ozonization was carried out in 2 bubble columns (2000 mm inlength and 100 mm in diameter (total volume 15.7 liters)). The apparatuswas equipped with a dosing pump to meter quinoline solution into thefirst bubble column and a further dosing pump to meter already ozonizedsolution from the first bubble column into the second bubble column.Each bubble column was provided with a device for metering fresh ozone.

[0187] Preparation: both bubbles were filled with 12 g of an aqueoussulfuric acid solution of quinoline (concentration as in Example 29).Ozone was then fed into the first bubble column to a quinoline contentof 15 g/l, and into the second bubble column to a quinoline content of 1g/l. The amount of gas was 10 Nm³/h in each case, the pressure was 5.3bar abs and the ozone content was 110 g/Nm³.

[0188] Continuous operation: 3.5 Nm³/h of ozone gas were fed into thesecond bubble column (with the low quinoline concentration), and 10Nm³/h of ozone gas were fed into the first bubble column. The quinolineconcentration was kept between 0.8 and 1 g/l by metering reactionsolution from the first bubble column into the second bubble column, thereaction solution withdrawn from the first column was replaced by thesame volume of fresh quinoline solution, and by withdrawing acorresponding amount of already ozonized solution from the second bubblecolumn, the volume of liquid therein was likewise kept constant. After afew hours, a uniform concentration of 12 g of quinoline/l wasestablished in the first bubble column. In the first bubble column, 97%of the ozone used reacted, and in the second bubble column 95% of theozone used reacted. No precipitation of PDC was observed. The ratios ofthe quinoline concentrations in the bubble columns correspondedreasonably accurately to the ratios of the amounts of ozone reacted.

[0189] The ozone consumption was measured and was about 107% of theory,calculated on the basis of quinoline. The ozone consumption was thusonly slightly higher than the consumption in the case of the batchprocedure under pressure.

[0190] 1 kg of sample was taken in each case from the continuousoperation at the start and at the end, this sample was oxidized andworked up as in Example 3 with H₂O₂.

[0191] The isolated PDC yield at the start of the continuous experimentwas 58.8 g/kg of sample (77%) and 6.1 g/kg of sample (8%), correspondingto an isolated overall yield of 85%, and at the end was 58.4 g/kg ofsample (76.5%) and 6 g/kg of sample (7.8%), corresponding to an isolatedoverall yield of 84.3%.

EXAMPLE 31 Comparative Experiment: PDC Continuously in the RecirculationApparatus

[0192] A recirculation apparatus as in Example 29 was operatedcontinuously:

[0193] 4 kg of an aquoeus sulfuric acid solution of quinoline(composition: 6% by weight of quinoline, 9.1% by weight of sulfuricacid, remainder water as in Example 29) are ozonized with 2500 l (STP)of O₂/O₃ with 100 g of O₃/Nm³ in a batchwise manner until the quinolinecontent had dropped to 0.9 g/l. Ozonization is then continued with thesame amount of gas and ozone concentration, and the quinolineconcentration is maintained between 0.7 g/l and 0.9 g./l as a result ofthe metered addition of aqueous sulfuric acid quinoline solution. Theoffgas comprised 63 g of ₃/Nm³ at the start of the continuous procedure,and 59 g of O₃/Nm³ at the end of the experiment. The ozone consumptionwas measured and was 230% of theory, calculated on the basis ofquinoline, which suggests massive secondary reactions and furtherreactions of the cleavage products. Finally, PDC began to precipitateout of the solution, which blocked the absorption column.

[0194] 1 kg of sample was taken in each case from the continuousoperation at the start and at the end prior to the precipitation of PDC,and this sample was oxidized as in Example 29 with H₂O₂.

[0195] The isolated PDC yield was 51.3 g/kg of sample and 5.3 g/kg ofsample at the start, corresponding to an isolated total yield of 74%,and at the end 47.2 g/kg of sample and 5.1 g/kg of sample, correspondingto an isolated total yield of 68.5%.

1. A process for the preparation of monocarbonyl or biscarbonyl orhydroxyl compounds by ozonization of unsaturated organic carboncompounds which have one or more olefinic or aromatic double bonds whichcan be cleaved by ozone in the molecule, and subsequent work-up of theozonization products, which comprises reacting unsaturated organiccarbon compounds which have one or more olefinic or aromatic doublebonds which can be cleaved by ozone in the molecule, a) in an organicsolvent or in aqueous solution in 1 to 2 steps continuously in equipmentconsisting of one to two absorption apparatuses, devices for dissipatingheat of the reaction and devices for separating the gas and liquidphase, with countercurrent reactant streams, with ozone instoichiometric amounts or in excess and b) converting the peroxideswhich form into the corresponding monocarbonyl or biscarbonyl orhydroxyl compounds either by continuous or discontinuous hydrogenation,oxidation or heating, depending on the reaction parameters from step a).2. The process as claimed in claim 1, wherein the continuous ozonolysistakes place in equipment consisting of two absorption apparatuses,devices for dissipating the heat of the reaction and devices forseparating the gas and liquid phase, with countercurrent reactantstreams, where the reactant is fed into the first absorption apparatusat a starting concentration which depends on the reactant used and thereaction conditions, whereas the ozone-bearing O₂-stream is introducedinto the second absorption apparatus at an ozone concentration whichdepends on the reactivity of the reactant, such that, in the firstabsorption apparatus, the reactant used is brought into contact with theozone stream which is fed into the first absorption apparatus afterpassing through the second absorption apparatus, as a result of whichthere is a deficit of ozone in the first absorption apparatus, then thereaction mixture, following the reaction of the ozone fed into the firstabsorption apparatus with the correspondingly introduced reactant,emerges from the first absorption apparatus, is separated into a gasphase and a liquid phase, and the liquid phase, which still comprisesunreacted reactant, solvent and the corresponding ozonolysis product, isfed into the second absorption apparatus into which the ozone-bearingO₂-stream with the desired starting concentration of ozone isintroduced, as a result of which there is an excess of ozone in thisapparatus, and then, when the reaction is complete, the reactionmixture, after emerging from the second absorption column, is againseparated into a gas phase and a liquid phase, and then the liquidphase, which now comprises only the corresponding ozonolysis product inthe solvent used, is passed to work-up stage b), and the smallpercentage of ozone present in the gas phase is optionally introducedinto the first absorption apparatus for the further reaction of newlyintroduced reactant.
 3. The process as claimed in claim 2, wherein theamount of ozone is chosen depending on the reactant used such that, forreactive substances, it corresponds to almost stoichiometric ozoneconsumption up to about 107% of the stoichiometric amount and, for lessreactive substances, an ozone consumption of about 107 to 140%,preferably up to 120%, of the stoichiometric amount, based on thereactant.
 4. The process as claimed in claim 2, wherein the startingconcentration of the reactant is between 1 and 3 mol/l, based on thedouble bonds, depending on the reactant used and the reactionconditions.
 5. The process as claimed in claim 2, wherein reactantswhich react relatively rapidly relative to the solvent or to theozonolysis product formed are preferably used.
 6. A process as claimedin claim 2, wherein the reactant stream is introduced into the firstabsorption apparatus and the ozone-bearing O₂-stream is also introducedinto the first absorption apparatus, some of the stream for the secondapparatus being diverted and fed into said apparatus, such that an ozonesplit is carried out, as a result of which there is again a deficit ofozone in the first absorption apparatus, and then, when the reaction inthe first absorption apparatus is complete, the reaction mixture isseparated into a gas phase and a liquid phase, the liquid phase, whichcomprises mainly the corresponding ozonolysis product in the solventused and residual unreacted reactant, is introduced into the secondabsorption apparatus, where it is brought into contact with the divertedozone stream, as result of which there is an excess of ozone in thesecond absorption apparatus, and then, when the reaction is complete,the reaction mixture is again separated into a gas phase and a liquidphase and the liquid phase, which now comprises only the correspondingozonolysis product in the solvent used, is passed to the work-up phase(step b).
 7. The process as claimed in claim 6, wherein the splitting ofthe ozone-bearing O₂-stream takes place in a ratio of first absorptionapparatus to second absorption apparatus of 50:50 to 90:10, where theO₂-stream fed into absorption apparatus 1 and 2 comprises 4-10% ofozone.
 8. The process as claimed in claims 6 and 7, wherein the reactantconcentration after leaving the first absorption apparatus depends onthe splitting ratio of the ozone stream and, in the case of a 90:10split, is preferably 0.1 mol/l to 0.5 mol/l and, in the case of a 50:50split, is preferably 0.9 to 2 mol/l.
 9. The process as claimed in claim2, wherein, if the reactants react rapidly relative to the solvent or tothe ozonolysis product formed, the ozonolysis is carried out in just onestep, in an absorption column.
 10. The process as claimed in claims 2-9,wherein the absorption apparatus used are apparatuses which effectgas-liquid exchange.
 11. The process as claimed in claim 10, wherein theabsorption apparatuses used are absorption columns, bubble columns,stirred reactors, stirred-tank reactors, mixers or loop reactors. 12.The process as claimed in claims 1-11, wherein bubble columns are usedas absorption apparatuses for the ozonolysis in the aqueous system. 13.The process as claimed in claim 12, wherein, the in the case ofozonolysis in the aqueous system, bubble columns are used as absorptionapparatuses and an ozone split is carried out according to claim
 6. 14.The process as claimed in claim 1, wherein the peroxides obtained instep a) are converted into the corresponding monocarbonyl or biscarbonylor hydroxyl compounds in step b) by continuous or discontinuoushydrogenation, in which the peroxide-containing ozonolysis productsolution obtained from the ozonolysis stage, and a hydrogen stream isintroduced into a hydrogenation apparatus which ensures an adequate masstransfer of hydrogen into the liquid phase and which has an initialcharge of a solvent and a hydrogenation catalyst, optionally withsimultaneous metered addition of a basic additive for regulating the pH,and the volume of the reactor solution is kept constant bylevel-controlled discharge via the filtration unit, as a result of whichthe peroxide content of the discharged solution, which is below 0.01mo/l is continuously controlled.
 15. The process as claimed in claim 12,wherein the hydrogenation apparatuses used are stirred-tank reactors,loop reactors, stirred or unstirred bubble columns or fixed-bedreactors.
 16. The process as claimed in claims 1-15, whereinmonocarbonyl or biscarbonyl or hydroxyl compounds of the general formulaI

in which Z is either OH or O and A, when Z is OH, is a single bond and,when Z is O, is a double bond Q is hydrogen or the radicals

where R₁ is H or an ester moiety derived from chiral or nonchiralprimary, secondary or tertiary alcohols, X is a straight-chain orbranched mono- or divalant, aliphatic alkyl or alkylene radical having 1to 50 carbon atoms, where this alkyl or alkylene radical may besubstituted by one or more groups which are inert under the reactionconditions; an optionally substituted, straight-chain or branchedaliphatic alkyl or alkenyl radical having 2 to 50 carbon atoms, whereone or more of the —CH₂ groups of the alkyl or alkylene chain isreplaced by an oxygen atom, a nitrogen atom, a sulfur atom or an —SO₂group; a radical of the formula —(CH₂)_(m)—O—CO—(CH₂)_(p), where m maybe an integer from 1 to 4 and p may be an integer from 1 to 6; a phenylor phenylene radical, where this phenyl or phenylene radical may besubstituted by one or more groups which are inert under the reactionconditions; a mono- or divalent alkylarylene or alkylene-arylene radicalhaving 7 to 50 carbon atoms, where these radicals may be substituted byone or more groups which are inert under the reaction conditions; anoptionally substituted heterocycle with one or two heteroatoms in thering or a single bond between two adjacent carbon atoms, and R ishydrogen, a C₁ to C₂₀-alkyl radical, —OR₁ or the radical

or X and R together form a mono- or bicyclic radical having 4 to 20carbon atoms which may be mono- or polysubstituted by groups which areinert under the reaction conditions, are prepared.
 17. The process asclaimed in claims 1-15, wherein the unsaturated organic carbon compoundswhich have one or more olefinic or aromatic double bond which can becleaved by ozone in the molecule used are compounds of the generalformula II

in which n is 0 or 1, Q₁ is hydrogen or the radicals

where R₁ is as defined in formula I, R₂ and R₃, independently of oneanother, are hydrogen, a C₁ to C₄-alkyl radical, a phenyl or pyridylradical which is unsubstituted or substituted by groups which are inertunder the reaction conditions, or are a —COOR₁ radical, or are a radicalof the formula (CH₂)_(m)—O—CO—(CH₂)_(p), where m may be an integer from1 to 4 and p may be an integer from 1 to 6, or, if n is 1 and Q₁ is theradical

R₂ and R₃ are together a single bond between two adjacent carbon atomsor are an alkylene radical having 2 to 4 carbon atoms if Y is ano-phenylene radical or an alkylene radical having 2 to 4 carbon atomsand R is a hydrogen atom, otherwise Y has the same meaning as X informula I, if n is 1, or if n is 0, is either hydrogen or, together withR₃ or with R₃ and the C═C double bond, is an optionally substituted,aliphatic, araliphatic, aromatic or heteroaromatic radical having 1 to50 carbon atoms which may be interrupted by oxygen, nitrogen or sulfur,or Y with R₃ and the C═C double bond is an optionally substituted mono-or bicyclic radical having 4 to 20 carbon atoms which can contain 1 or 2heteroatoms from the group S, N or O, or Y and R together form a mono-or bicyclic radical having 4 to 20 carbon atoms which can be mono- orpolysubstituted by groups which are inert under the reaction conditionsand R is as defined in formula I.